But what if several members of a group all brought their Bluetooth speakers to the same gathering? And what if you wanted to fill a large space like a picnic area or a rave warehouse with sound from this collection of devices?

Then you’d need some way to sync up the devices so they can all play the same song at the same time. But Bluetooth signals, unfortunately, peter out after just 30 feet, and they can’t easily be used to broadcast to multiple devices.

That’s exactly the problem San Francisco-based Boombotix is now trying to solve with a new iOS app called Boombotix Sync. The startup hopes to raise at least $15,000 on Kickstarter to fund the development of the app and buy the central servers needed to make it work.

The cloud-based system behind the app, which broadcasts the same signal to multiple iOS devices over cellular data networks, was originally conceived as a way to sync up multiple Boombot speakers in a single location without cables (imagine, for example, a mob of bicyclists tooling down the street with their Boombot Rex speakers clipped to their bikes, as in Boombotix’s Kickstarter video). But it also allows people in separate locations to listen to the same playlist simultaneously.

“We do want this sense of connection, especially when we listen to pop music,” says Lief Storer, the founder of Boombotix and the inventor of Sync. “Like, with my girlfriend, we could be hundreds of feet apart but there is still this feeling that we are doing this activity together. Sharing the same listening experience is something that makes you feel connected.”

As of this writing, the company was about two-thirds of the way to its funding goal. In return for their Kickstarter donations, backers of the project will receive a “pro” subscription to the Sync app, allowing them to act as the broadcaster or “DJ” who controls what other listeners are hearing. (There’s also a free version of the app that allows unlimited listening and 10 minutes of DJ time.) If Boombotix reaches its stretch goal of $50,000 on Kickstarter, it will develop an Android version of the app.

Sync isn’t the first technology that synchronizes speakers wirelessly: that’s also one feature of home audio systems from companies like Sonos, as well as an iOS7 app called Seedio. But the existing systems only work over a local WiFi network. Storer says Boombotix wanted to build a system that would synchronize multiple phones and speakers over cellular data networks, so that users could share music anywhere they have 3G, 4G, or LTE connections. “This wasn’t possible five years ago, but LTE has opened up the doors to doing a piece of technology like this,” says Storer, who has filed for a patent on his technology. (He’s shown on the far-right bike in the photo above.)

In principle, multiple users could stream the same song to their devices (and any paired Bluetooth speakers) at the same time using a service like Spotify, Rdio, or Pandora. But in practice, it would be impossible to start all the streams at the same moment. The key to making Sync work, according to Storer, is to stream music to all listening devices from the same server, while correcting for the measurable delays in transmission over the Internet and wireless networks, as well as the differing audio-processing latency of individual iOS devices.

“It’s usually noticeable when you have a difference of as little as 30 milliseconds between devices,” Storer says. “That’s where the heavy lifting had to go. We have a central NTP [Network Time Protocol] server to get the devices as close as possible.” There’s also a jog dial in the app that lets users shift the timing of the streams manually by up to 100 milliseconds in either direction.

Boombotix is four years old, has been selling portable speakers since 2010, and probably could have funded the development of Sync on its own. But the company has had some admirable luck on Kickstarter: last year it raised almost $130,000, more than four times its goal, to fund development of the Boombot Rex, its latest speaker model.

Storer says he sees Kickstarter as a marketing channel, not just as a fundraising venue. “Kickstarter is not necessarily a place to raise money for R&D,” he says. “It’s more like a litmus test for your product. If we put out a project and we heard a pin drop, that would be an immediate red flag and maybe it would be a good time to pull the plug.”

There are 23 days left in the Boombotix Sync campaign. If all goes well, Storer says, Boombotix will submit Sync to Apple’s iTunes App Store in mid-December and will be able to launch the cloud service in time for New Year’s Eve. “We have this vision for creating a playlist that we’ll sync up to on New Year’s Eve from anywhere in the world,” he says. “That’s kind of our group party for everyone who participated.”

Here’s the Kickstarter video for the Boombotix Sync project.

Wade Roush is a freelance science and technology journalist and the producer and host of the podcast Soonish. Follow @soonishpodcast

This is exactly what I was thinking about… And I guess that when we’ll all be watching our own tv programation…somebody will come around with the great idea off some king of sharing programation that he would call tv channel…LOL…I wish I was 16 and everything would appears to me as revolutionary.

budtobud is already doing this on Mac OS X with Rdio and will be adding Spotify and support for IOS devices shortly. We’ve covered all of these issues and more. You can check out a recent review of our app at http://bit.ly/17lN6xR.